序列密码也称为流密码（Stream Cipher），它是对称密码算法的一种。序列密码具有实现简单、便于硬件实施、加解密处理速度快、没有或只有有限的错误传播等特点，因此在实际应用中，特别是专用或机密机构中保持着优势，典型的应用领域包括无线通信、外交通信。若能以一种方式产生一随机序列（密钥流），这一序列由密钥所确定，则利用这样的序列就可以进行加密，即将密钥、明文表示成连续的符号或二进制，对应地进行加密。-Stream cipher is also known as Stream Cipher (Stream Cipher), it is a symmetric encryption algorithm. Stream ciphers achieve a simple, easy to hardware implementation, the encryption and decryption processing speed, there is no or only limited error propagation characteristics, in practical applications, especially proprietary or confidential agency maintains advantage Typical applications include wireless communication and diplomatic communications. If in a manner to generate a random sequence (keystream), this sequence is the determined by the key, then the use of such sequences can be encrypted, upcoming key expressly into successive symbols or binary, corresponding to encrypted.